Evaluation of different samples pretreatment method of MALDI-TOF MS on the identification of common foodborne pathogens

ObjectiveTo evaluate the effects of different sample pretreatment methods of MALDI-TOF MS on the identification of common foodborne pathogens.

MethodsA total of 51 common foodborne pathogens were collected, covering Salmonella, Staphylococcus, Listeria, Vibrio, Escherichia, and Shigella.Then the effects of three sample treatment methods including direct smear method, in-situ formic acid extraction method and formic acid acetonitrile extraction method of MALDI-TOF MS on the identification of common foodborne pathogens were evaluated.

ResultsThere were no significant differences in the identification results of Salmonella, Shigella, and Escherichia by three sample pretreatment methods; Staphylococcus captis, Staphylococcus cohnii, Vibrio parahaemolyticus and Vibrio vulnificus could not be identified effectively by direct smear method, but these strains could be accurately identified by other methods.Non-listeria monocytogenes strains of listeria genus were often mistakenly identified by using direct smear method and in-situ formic acid extraction method, and the use of formic acid and acetonitrile extraction could improve the identification accuracy for different species of listeria.

ConclusionDifferent sample pretreatment methods of MALDI-TOF MS have certain influence on the identification of common foodborne pathogenic bacteria.Therefore, selecting appropriate sample pretreatment methods is important to obtain reliable and accurate identification results.